Semi-blind channel identification and equalization in OFDM: an expectation-maximization approach

The paper proposes an expectation-maximization approach to channel identification and equalization in OFDM. The algorithm exploits the natural constraints imposed by the channel (sparsity, maximum delay spread, and a priori statistical information) and those imposed by the transmitter (pilots, cyclic prefix, and the finite alphabet constraint). These constraints are used to reduce the number of pilots needed for channel and data recovery and also to perform this task within one packet.